Improved process of calcining ores and minerals



B. KEITH, A. BEHR & N. S. KEITH. rnoonss 0F GALGINING ORES AND MINERALS.

No. 36,437. Patented Sept. 9, 1862.

[mew/for UNITED STATES PATENT .OFFICE.

BETHUEL KEITH, ADOLPH' BEHR, AND NATHANIEL SHEPARD KEITH, or NEW YORK,N. Y.

IMPROVED PROCESS OF :CALQ-lNlNG QRES AND MINERALS..

$pecificaiion forming part of Letters Patent No. 36.437, dated September9, 1862.-

To all-whom it may concern:

Be it known that we, BETHUEL KEITH, ADOLPH BEHR, and NATHANIEL SHEPARDKEITH, all of the city of New York, in the county of New York, in theState of New York, have invented a newand improved mode of oxidizing,or, as technically termed, roasting or calcining, oxidizable metals,oxidizable substances, and the various ores, and reduc-' diffusedthrough the air, which is introduced therewith in quantities sufficientto support the combustion and oxidation. This process is particularlyapplicable to ores known as bisulphurets and sulphurets.

. To enable othersto understand perfectly the' process and its results,we'will procced't'o de-, scribe the operations.

' To effect a complete oxidation or reduction of metals and ores, it isnecessary to expose them to the action of heat and air When thematerials are in a state of minute division and well diffused throughair, intense heat will quickly oxidize all the oxidizable substances,and at the same time will melt and fornrinto globules all the particlesof unoxidizable metals present. These results may'be accomplishedby'theaid of apparatus such as is exhibited by the accompanyingdrawings.

1 represents a reverberatory furnace or oven, built of fire-brick'andclay, so as to resist the heat. A fire of wood or coal is kindled in thefire-space B, allowing a draft through the draft-channel A, and thelower end of the pipe G being above the surface of the water I in thereservoir H, the draft will be sufficient to support combustion. As soonas the fire is well burning, the blast of air from the blower is startedand communicated to the flame O by means of the pipe D. This operationproduces an intense oxidizing-flame for some distance in theoven E E E.The surface'of the water in .the reservoir-is now raised, so astq coverthe end ofthe pipe c. The finely-divided material to be oxidizedorreduced is now introduced into the blower, and is, with the air,

carried directly into the 'flame..- The intense heatand free access ofair instantly completes the oxidation and reduction. The now oxidizedand reduced substances pass into the chamber F, where the heavierparticles settle to the bottom, while the lighter particles, to-

gether with the gases and volatilized sub stances, pass through the pipeG, leading from the top of the chamber to the water I in thereservoir-H. Here the water takes up these light particles and thecondensable gases, and allowing the uucondensed gases to pass offthrough the chimney K. The blower used may be any kind which will givemotion tothe finely-divided particles introduced therein, and at thesame time keep up a continuous and steady blast of air. In cases wheresulphnrets and bisulphurets are oxidized,and

it is desirable to collect in its purity the sulphuric acid generatedand set free by the process, the chamber F must be made of asufiicientlength, or a series of chambers may be connected, so as toallow all of the fine particles to settle, and nothing but the gaseoussubstances enter the water, where the sulphuric acid'will be'readilycondensed and absorbed.

The principal advantages of our process are First: A complete oxidationof all oxidizable substances is effected, as they are exposed to thefree access of air and an intense heat. Their diffused condition givesthem no chance to melt or cake together.

Second. All of the particles of unoxidizable metals-such as gold,silver, &c.-are in the intense heat melted into globules, so that by asubsequent washing or amalgamating they may be readily collected withoutloss.

'Third- It requires the least time and the least expenditure of fuel, aseach particle is instantly oxidized and passes off, the quantity beingso regulated as to make use of the heat;

2 r d 1 A 36,437

sulphurous and other gases are driven out of the chamber and reservoirbefore the oxidized substances are withdrawn.

Sixth. In cases where ores and metals of difl'erent specific gravitiesare mixed, it effects their separation mechanically and without extralabor. 4

. Seventh. The sulphurous acid generated by the former processes ofroasting of sulphurets and bisulphurets is by this process furtheroxidized into sulphuric acid, the free access of air and the intenseheat being the conditions which cause this change. The sulphates formedduring former processes at the intense heat of our process give offtheir sulphuric acid. This acid may be collected. as before described,and is useful in separating silver and gold.

What we claim as our invention, and desire to secure by Letters Patent,is- Y A mode or process of oxidizing (or roasting or calcining) alloxidizable substances-suchas metals, minerals, sulphurets, bisulphurets,and oresand at the same time and operation reducing to. a metallic statesuch unoxidizable metal as may be present therein, by the use of theapparatus and in the-manner herein described, or any other apparatus ormanner' substantially the same, and-which will produce theintendcdresults.

BETHUEL KEITH, ADOLPH' BEH'R. N. SHEPARDKEITH.

Witnesses:

W. I..MooRE, Giro. H. KEITH.

